Heat shrinkable sheet material has found increasing use in sealing around telecommunications cables where the outer sheath has been cut away to expose the inner conductors for splicing to another cable. One commom splice is known as a branch-off splice. In such a splice the conductors of a smaller diameter cable are electrically connected to certain of the conductors of a larger diameter cable to branch off from the larger diameter cable. The branch cable may be used to carry telephone service to a number of houses in a neighborhood while the larger diameter cable may terminate in the splice closure or continue down the street. The heat shrinkable material is wrapped around the cables to fully enclose the splice area, and it has a hot melt adhesive on its inner surface facing the cables. At the end where both the larger diameter cable and the smaller diameter cable exit from the sheet material the heat shrink material must be held together between the cables while the heat shrinkable material is heated and shrunk to seal completely around both cables.
Cable branch-off sealing members for holding the layers of heat shrinkable material together while the sheet material is heated and shrunk to create a waterproof seal around the cables are disclosed in U.S. Pat. Nos. 4,246,687 and 4,298,415; European Patent Application Publication Nos. 50,995; 68,780; and 79,245, and West German Patents No. DE 3105471/A1 and No. DE 3204866/A1. Many of these are unduly complex for manufacture or use.